1. Field of the Invention
This invention relates to a novel wax-like substance possessing surface activity characteristics, and to a process for producing the same. More particularly, the invention relates to hydroxyalkyl-etherified glycolipid esters represented by formula (I), ##STR3## wherein R.sup.1 represents a methyl group or a hydrogen atom, R.sup.2 represents a saturated or unsaturated hydrocarbon group having 11 to 15 carbon atoms when R.sup.1 is a methyl group and R.sup.2 represents a saturated of unsaturated hydrocarbon group having 12 to 16 carbon atoms when R.sup.1 is a hydrogen atom, R.sup.3 represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, A represents --CH.sub.2 --CH.sub.2 --O-- or ##STR4## and a,b,c,d,e,f and g represent integers whose sum ranges from 1 to 60, and represented by formula (II), ##STR5## wherein R.sup.1, R.sup.2 and A are the same as defined above, and s,t,u, v,w,x,y, and z represent integers whose sum ranges from 1 to 60.
2. Description of the Prior Art
Esters of a long-chain fatty acid and a long-chain alphatic alcohol, long-chain hydrocarbons, glycerides, lanolin and the like, all known materials, are wax or grease-like materials. The esters have been widely used as glazing materials and oily substances for leather, cosmetics and ointments, lubricants for fibers, machinery, stationery, printing, rust inhibition and insulation and have been used in metal processing. In recent years, was has often been used in emulsified form with a surface active agent in view of its safety and easy handling. However, formulation technique of a high degree is required for emulsification of wax because the wax characteristics depend directly upon such formulation technique.
Extremely high formulation techniques only permit wax to exhibit all of its inherent characteristics, but this involves such difficulty. Hence, there has been a strong desire for the development of a wax possessing surface activity.
Wool wax, which is known under the name of lanolin, includes in its structure a peculiar ester bond formed between the long-chain branched fatty acid and the long-chain branched aliphatic alcohol or steroid alcohol, it is a wax substance having both an excellent wax-like property and a proper emulsifying ability. However, wool wax is a mysterious naturally occurring compound and does not find wide applicability partly because its combination with other materials require highly advanced techniques and partly because the amounts used are limited because of its peculiar animal smell.
In view of that situation, the present inventors have conducted a wide variety of studies on the development of a compound possessing a surface activity and wax-like properties, and have found that a glycolipid ester represented by the formula (III) exhibits the desired activity and properties. ##STR6## wherein R.sup.1, R.sup.2 and R.sup.3 are the same as defined above.
However, the glycolipid ester of the formula (III) lacks heat stability at high temperatures and viscosity. The reason is that the hydroxy group of the sugar moiety of this compound exists in a free form, thereby resulting in reduced adhesiveness, lubricity, flexibility and plasticity.
A further study was made in order to improve the above-mentioned properties arising from the sugar structure and as a result various derivatives of the glycolipid ester of formula (III) have been synthesized by chemical modification of the hydroxy groups. After investigating the characteristics of these derivatives, it has been found that the compound of formula (I) obtained by modification of the hydroxy groups with hydroxyalkyl groups, and the compound of formula (II) produced by modification of the hydroxy groups and carboxyl group with hydroxyalkyl groups possess the above desired characteristics. A novel process for producing the same has also been discovered.